why would a hotel keep large quantities of acid, and why try to dispose of it in such a hasty manner?

Not making excuses for the hotel because I can tell from the symbolism that this hotel is probably a place where minors are being sexually abused for the amusement of the savages.

They have a rooftop pool at the hotel. Muratic acid is used for cleaning concrete. What could have happened is that they cleaned the concrete around the pool and the pool itself with the acid. IF the surfaces are made of concrete. Then they washed off the concrete into the pool, rinsed the acid off the inside of the pool with the drain open, and let the whole mess run into the sewer.

This scenario ONLY works if the surfaces are concrete. If the surfaces are not concrete then I cannot think of any reason to have two barrels of muratic acid on hand at that hotel.

I made the mistake of mixing acid and chlorine together one day when I was cleaning bricks and I thought it had damaged the inside of my lungs forever. I got over it but its a deathly mix.